BIODEGRADABLE MICROPARTICLES FOR LONG ACTING INJECTIONS

  Despite several methods for preparation of injectable microparticles with incorporated water-soluble component are described, the most appropriate process based on “double emulsification” approach was selected.

 Briefly, the concentrated water solution of the highly water-soluble active compound (Glatiramer acetate) was dispersed in the solution of the biodegradable polymer in water-immiscible volatile organic solvent (methylene chloride or chloroform). 

Obtained primary “water-in-oil” (w/o) emulsion was further dispersed in continuous external water phase containing surfactant.

 Particle size of the formed “water-in oil-in water (w/o/w) double emulsion” droplets depends on the amount of applied force at this step, namely on mixer size and type, mixing speed, surfactant type and concentration, etc., and can be regulated in relatively wide range, from 1 to 50-100 mcm. 

After evaporation of the organic solvent microparticles solidify and can be collected by filtration or centrifugation. Collected g loaded microparticles (MP) were washed with purified water to eliminate most of surfactant and non-bond peptide and centrifugated again. Washed MPs were collected and lyophilized without additives (“as is”) or with addition of cryoprotectant (mannitol) to facilitate reconstitution after lyophilization. Lyophilized samples were stored in refrigerator.